Determination of primary bands for global ocean-color remote sensing

A few years ago, Lee and Carder(1) demonstrated that for the quantitative derivation of major properties in an aqua-environment (information of phytoplankton biomass, colored dissolved organic matter, and bottom status, for instance) from remote sensing of its color, a sensor with roughly similar to 17 spectral bands in the 400 - 800 nm range can provide acceptable results compared to a sensor with 81 consecutive bands (in a 5-nm step). In that study, however, it did not show where the 17 bands should be placed. Here, from nearly 300 hyperspectral measurements of water reflectance taken in both coastal and oceanic waters that covering both optically deep and optically shallow waters, first and second derivatives were calculated after interpolating the measurements into 1-nm resolution. From these hyperspectral derivatives, the occurrence of zero value at each wavelength was accounted for, and a spectrum of the total occurrences was obtained, and further the wavelengths that captured most number of zeros were identified. Because these spectral locations indicate extremum (a local maximum or minimum) of the reflectance spectrum or inflections of the spectral curvature, placing the bands of a sensor at these wavelengths maximize the possibility of capturing (and then accurately restoring) the detailed curve of a reflectance spectrum, and thus maximize the potential of detecting the changes of water and/or bottom properties of various aqua environments with a multi-band sensor.